1. Field of the Invention
This invention relates to a tape processing device which can properly deal with a tape having an adhesive layer, such as an adhesive tape used as a printing tape.
1. Prior Art
Conventionally, there has been proposed e.g. by Japanese Laid-Open Patent Publication (Kokai) No. 6-8194, a tape processing device of this kind, which is applied to a tape printing apparatus for obtaining labels from a printing tape. The proposed tape printing apparatus is loaded within its casing with a tape cartridge accommodating a roll of an adhesive tape having on its back an adhesive layer which is covered with a peel-off paper (peel-off paper-backed adhesive tape). The adhesive tape is rolled out from the tape cartridge, and a print head is pressed against the adhesive tape to thereby effect printing on the tape. Then, the printed portion of the tape is brought to a position before a scissors-like cutter and cut off by the cutter to a predetermined length. Then, the cut-off piece of the adhesive tape is delivered from the apparatus via a tape exit formed in the casing. The cut-off piece, which was printed, can be affixed to a file or the like as a label after removing the peel-off paper therefrom. In the above process of preparing a printed label from the printing tape, when the adhesive tape is cut off by the cutter, the adhesive of the adhesive tape can adhere to cutting blades of the cutter to cause various inconveniences. For example, the cutting blades can be disabled from moving, or the cut-off piece is affixed to the blades to be jammed into the tape exit or cut again.
On the other hand, scissors have been proposed e.g. by Japanese Patent (Kokoku) No. 3-4237, which are constructed to prevent an adhesive of an adhesive tape from adhering to cutting blades thereof. The scissors are comprised of a fixed blade (blade to which its support shaft is fixed) and a movable blade each of which has its inner sides baked with a coating of a fluorine resin to thereby prevent the adhesive from adhering to the cutting blades when the adhesive tape is cut off.
In the light of this prior art, it is contemplated that the baking of a coating of a fluorine resin on the cutting blades of the cutter can be a solution to the above inconveniences of the cutter employed in the conventional tape processing device. However, the baking of the coating of fluorine resin complicates the manufacturing process of the cutter and increases the manufacturing cost of the same, resulting in an increase in the whole manufacturing cost of the tape processing device. Further, in practice, the baked coating of the fluorine resin is not provided on a cutting edge portion so as to prevent degradation of the cutting performance of the cutter. As a result, it is impossible to preclude the occurrence of adhering of an adhesive and the cut-off piece of the adhesive tape to this portion of the cutter.
Further, the cutter of the proposed tape processing device is a scissors-like type which is comprised of a fixed blade and a movable blade pivotally connected by a support shaft, and the movable blade rotates to cut off a strip of the tape which is brought to a position in line with the fixed blade fixed to a frame of the device. The cutting edges of the fixed blade and the movable blade are formed to have a linear or straight profile similarly to typical scissors.
Since the fixed blade and the movable blade are each formed with a cutting edge which extends in a straight line (straight cutting edge), the cutting edge angle formed by the cutting edge of the fixed blade and that of the movable blade decreases as the depth of the cut into the tape increases. Further, due to limited space within the device, an initial cutting edge angle cannot be set to a very large value. More specifically, the cutting of the tape is started with a cutting edge angle of the blades opening at one side of the tape in the direction of the width of the tape being equal to approximately ten degrees, and terminates with a cutting angle of the same at the other side of the tape being equal to approximately two degrees. As the tape is cut to a larger depth, the cutting edge angle becomes smaller, and inversely, the resistance to the cutting action becomes larger. Therefore, it is required to progressively increase the cutting torque as the cutting process proceeds. Moreover, as the depth of the cut is increased, the edge-to-edge crossing point (point of action or working point) becomes farther from the support shaft (fulcrum), so that according to the principles of the lever and fulcrum, it is required to increase the cutting torque all the more. Therefore, the cutting torque to be applied at the point of application of force varies in a wide range, and especially when the tape is automatically cut, a drive source from which torque is obtained for the automatic cutting operation is required to have a large output power to make the same adapted to a peak of possible required cutting torque.
Further, Japanese Laid-Open Patent Publication (Kokai) No. 8-58203 proposes a tape printing apparatus similar to the above, which uses a tape cartridge having a casing formed of a resin mixed with a conductive material, such as carbon, and receives the tape cartridge in a cartridge compartment formed of a resin mixed with a conductive material, such as carbon, and at the same time connected to a ground, in a manner cooperative with the casing of the tape cartridge. This configuration of the tape printing apparatus and the tape cartridge grounds the tape having static electricity generated thereon through friction of the tape with other component parts, which occurs during the manufacturing process of the tape and when the tape is rolled out, to thereby prevent the static electricity from adversely affecting the component parts of the device.
According to the proposed tape printing device, however, since the tape cartridge is simply connected to the ground, it is impossible to eliminate or dissipate static electricity from the charged tape due to the nature of static electricity. That is, since a static-reducing member is not brought into contact with a whole surface area of the tape from which static electricity should be dissipated, static electricity cannot be fully dissipated from the charged tape. Further, the tape is newly electrified or charged through friction thereof with passage members and other component parts of the device even when it is rolled out from the tape cartridge and advanced to the tape exit for delivery therefrom. Therefore, when the tape is automatically cut, a piece of the tape cut off by the cutter can adhere to the tape exit due to its static charge, resulting in re-cutting or jamming thereof.